Ive got a few questions about SMC and the proper way to repair it using Duramix products. I just started working at a new shop a Ford dealership, my last shop used a combo of Fusor and 3m. Also SMC repairs were next to none at my prevoius place, so I just have small basic understanding.

One of my current projects is a 96 mustang hood. The front corner got knocked loose due to a collision. After removing the damage and my taper i was left with roughly a chuck of 3/4 by 3/4 section gone from the corner.

I tapered it out about 1/4 inch is that a good taper or do I need more of taper??

One of the guys said to fill the gap with 4050 which is SMC backer adhesive, rough it to shape then use 4058 plastic adhesive cosomtic filler. Is that a good method?? Is the use of the 4050 a good idea to fill my gap with?? Can you use 4058 for this purpose??

How about a high density SMC filler?? My parts guy brought me some stuff made by UPOL, but I had all ready applied the 4050. I used the UPOL filler to fill my voids from the 4050 this a good idea?? I noticed the UPOL filler spread like crap and was very hard to get a good smooth surface without any voids.
I got a suggestion of using Evercoat's Poly Flex filler to fill my small voids in the UPOL good idea??

Basically I need to know what I can use to repair this stuff. I know you cant apply regular filler over SMC due to the different expansion rates. What can I use the UPOL SMC filler for, what are the limits of this stuff?? If I get small pinholes or voids can I use some other type product that sreads easier over the UPOL or am I just out of luck??? What are you SMC guys using...Thanks Eric

Originally posted by sevt_chevelle Ive got a few questions about SMC and the proper way to repair it using Duramix products. I just started working at a new shop a Ford dealership, my last shop used a combo of Fusor and 3m. Also SMC repairs were next to none at my prevoius place, so I just have small basic understanding.

One of my current projects is a 96 mustang hood. The front corner got knocked loose due to a collision. After removing the damage and my taper i was left with roughly a chuck of 3/4 by 3/4 section gone from the corner.

I tapered it out about 1/4 inch is that a good taper or do I need more of taper??
************************************************** *
The taper should be as graduated and exaggerated as you can make it. Most important.
BWK

One of the guys said to fill the gap with 4050 which is SMC backer adhesive, rough it to shape then use 4058 plastic adhesive cosomtic filler. Is that a good method?? Is the use of the 4050 a good idea to fill my gap with?? Can you use 4058 for this purpose??
**************************************************
4050 with 4058 is my preferred method, do not use 4058 in place of 4050.
BWK

How about a high density SMC filler?? My parts guy brought me some stuff made by UPOL, but I had all ready applied the 4050. I used the UPOL filler to fill my voids from the 4050 this a good idea?? I noticed the UPOL filler spread like crap and was very hard to get a good smooth surface without any voids.
I got a suggestion of using Evercoat's Poly Flex filler to fill my small voids in the UPOL good idea?
***********************************************
UP SMC filler is very brittle, works good for scrapes pinholes
also noticed it has a high shrinkage rate if used thick.
BWK

Basically I need to know what I can use to repair this stuff. I know you cant apply regular filler over SMC due to the different expansion rates. What can I use the UPOL SMC filler for, what are the limits of this stuff?? If I get small pinholes or voids can I use some other type product that sreads easier over the UPOL or am I just out of luck??? What are you SMC guys using...Thanks Eric

*******************************************
The Duramix is your strongest fix on the SMC and it sounds like you did it right.
My question would be ? you did not put the UP filler over the 4050
did you? Polyesters do not stick to duramix without a barrier-coat and will bubble first day or so in sun.
BWK

Barry I did in fact apply the Upol filler over the 4050. The supplier stopped by as I was doing this and this what he suggested to use. So I do have UPOL over my 4050.

When I asked him how he would have done it he said would have used just the UPOL filler to fill gap.
So what you are saying is that my UPOL stuff is mostly good for small voids???

Does Upol make different types of fillers for this purpose, the stuff I used was white and looked like duraglass.

On a two sided repair where you have access to both sides what should you use for a backer piece? Fiber cloth, light cure patches or scrap SMC if you have it??
Wanting any type of info about SMC so the next time am not worring if this will come back. Thanks...Eric

Originally posted by sevt_chevelle Barry I did in fact apply the Upol filler over the 4050. The supplier stopped by as I was doing this and this what he suggested to use. So I do have UPOL over my 4050.
**********************************************

I think, it was a mistake? I know UP says do it but, I have never seen any polyester last over Duramix (liquid polyurethane) long term with out using an epoxy or a 2K primer as a barrier coat first.
Hope for the best, but if you get a bubble than you will know.
bwk

When I asked him how he would have done it he said would have used just the UPOL filler to fill gap.
So what you are saying is that my UPOL stuff is mostly good for small voids???
**********************************************
UP has some good stuff but the President of the company is a real salesman! The SMC repair they will demo how flexible it is on a piece of paper when it dries (and it is) than the salesman is taught to destroy the paper because 3-8 hours later it will crack like crazy. The SMC repair is good stuff for gouges and voids and easy to use but not for a hole where it will need real strength to fight expansion everyday.
bwk

Does Upol make different types of fillers for this purpose, the stuff I used was white and looked like duraglass.
*******************************************
No, they have it in 3 colors, black, gray and white-same stuff.
bwk

On a two sided repair where you have access to both sides what should you use for a backer piece? Fiber cloth, light cure patches or scrap SMC if you have it??
Wanting any type of info about SMC so the next time am not worring if this will come back. Thanks...Eric

*************************************************
With the Duramix or Plasto mix, I never use a mat or cloth or back on a small hole under 4-5 inches in size. I prep the back side and lay the wrapper it comes in over the back side of hole than tape a body filler spreader to the plastic for holding power. Than from the front side spread the 4050 in the hole. In about 15 minutes pull the wrapper off the back side and it leaves the duramix smooth and about 90% blocked and finished so it takes very little effort to buzz with and 80 grit to finish out for primer.
This will not work with 3M or fuzor as they are not strong enough.
Than on the front side finish out with 80, the Duramix will not sand good with finer grits and you will just heat up the area and have real problems. If I need a skim finish coat at that point I will spread a thin coat of 4050 again and sometimes use the 4058.
bwk

One further note, UP will tell you that that SMC stuff is strong enough to bond panels-BS it has about 700-800lbs lap sheer about a fourth of the two part products.
bwk

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